Opaque pen
It's difficult to find pens that remain a pure purple on non-white paper or other media. This will do the trick, but it is never going to be used for "fine liner" situations. I haven't had it long enough to know about the product's longevity for ink and writing smoothly...so far, it maintains its true color on all colored papers, goes on without skipping, and dries evenly. I haven't used it on other surfaces other than paper products. The pen need priming with strong shaking and pumping the tip on scrap paper, follow directions given.